Lightweight, sliding-jaw, pipe wrenches are described in, for example, U.S. Pat. No. 2,656,751 (issued to W. J. Johnson et al.) and U.S. Pat. No. 2,680,984 (issued to C. H. Ingwer). FIG. 1 shows a lightweight, sliding-jaw pipe wrench from U.S. Pat. No. 2,656,751 (the '751 patent). The pipe wrench of FIG. 1 consists of a handle 10 having a fixed jaw 11 and an integral frame 12 through which extends a threaded shank 13 of a movable jaw 14, which is adjustable relative to the jaw 11 by a nut 15 engaging the shank 13 and supported and retained between the frame 12 and a pair of bosses 16. The jaws 11 and 14 are provided with replaceable jaw inserts 17 and 18, respectively. The '751 patent describes the pipe wrench as being formed essentially of a metal or alloy that is lightweight and that does not have as high a yield point under proof as malleable iron and steel. The '751 patent describes designing and proportioning various elements of the pipe wrench to compensate for the low yield point of the lightweight material. For example, as disclosed in the '751 patent, the handle 10 has an H transverse cross-section.
Pipe wrenches such as described above are available in the market. For example, the Rigid Tool Company makes a variety of such pipe wrenches under the trade name RIDGID®. Lightweight, sliding-jaw, pipe wrenches such as described above are commonly used in downhole tool service facilities to apply high connection makeup torques. Typically, these wrenches are attached to an overhead crane when being used. Safety has been a concern with these wrenches when operating at high torque loads. Bent handles and fractured jaws are a common occurrence for such wrenches, which can result in jaws becoming air borne, handles swinging free violently, and overhead cranes being shocked and potentially damaged.